Measurement of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in patients with knee osteoarthritis: comparison with generalized osteoarthritis

Objectives. To compare plasma levels of matrix metalloproteinase (MMP)-3, M MP-9 and tissue inhibitor of metalloproteinases-l (TIMP-1) between patients with knee osteoarthritis and normal subjects, to investigate whether the d egree of knee joint involvement is related to those measurements, and to co mpare patients with and without generalized osteoarthritis. Methods. Eighty-three women with knee osteoarthritis (OA patients) were stu died. Plasma levels of MMP-3, MMP-9 and TIMP-1 were measured by enzyme immu noassays. Knee and hand radiographs were taken of all patients. The joints of the knee and hand were graded from 0 to 4 according to Kellgren and Lawr ence criteria. All OA patients were divided into a generalized OA (GOA) gro up (n = 37) and a knee OA (KOA) group (n = 46) according to Doherty's crite ria. MMPs and TIMP were also measured in 19 normal subjects. Results. Plasma levels of MMP-3 and TIMP-1 were significantly higher in OA patients than in normal subjects. In contrast, MMP-9 was lower in OA patien ts than in normal subjects. Plasma levels of MMP-3 and MMP-9 were not influ enced by the grade of knee OA. TIMP-1 was influenced by the grade of knee O A. Plasma levels of MMP-3 were significantly elevated in GOA compared to KO A. In contrast, there were no significant differences in plasma levels of M MP-9 and TIMP-1 between GOA and KOA. Conclusion. Since the plasma level of MMP-3 in GOA was higher than that in KOA patients, it may be a superior indicator for whole-joint degeneration.